Flashcards in Class 3: Peptide Hormones Deck (20):
LH and FSH
(From Pituitary): In ovary, stimulates development of ovarian follicles; In testes, regulates function of Sertoli cells (somatic cells within the testes that support sperm development) in the seminiferous tubules (compartments in which male gametes grow)
(From Pituitary): Secretion of steroid hormones from the gonads by binding to and stimulating steroidogenic cells (ovary & testes), regulates ovulation in females.
(From Hypothalamus) endocrine communication via blood vessels to the pituitary
delivery of the peptide hormone (or any other molecule) from out of the cell through secretory machinery (vesicles).
Endoplasmic reticulum :
Organelle where translation of proteins that are destined to leave the cell occurs.
peptide hormones are secreted proteins that pass through the lipid bilayer and exit the cytoplasm to serve a function elsewhere in the cell.
cell membranes consist of a lipid bilayer and membrane proteins which accomplish vital biological functions. The ones we focused on in class were membrane receptor proteins which serve as the connection between intracellular and extracellular activity.
Differential gene expression
Only certain genes are transcribed in each cell type
molecule that binds
Steroid hormone receptor aka nuclear receptor:
Class of receptors: Androgen/ Estrogen/ Progesterone Receptors that consist of a DNA binding domain, a ligand binding domain (where T,E, P attach), and other “variable” factors. This receptor attached to the HRE (Hormone Response Element) & via a transcription factor begins transcription of DNA to RNA.
Positions the receptor in the plasma membrane, this domain is actually in the lipid membrane (hydrophobic/ lipophilic)
Binds ligand (the peptide hormone); in the family: FSH-R, LH-R, GnRH-R
proteins closely coupled to the receptor, and initiate the intracellular signal transduction events.
Second messengers tend to be very small molecules. I.e. cAMP (Cyclic AMP)
enzymes that add phosphate groups to their substrates.
the process of adding a phosphate group, phosphorylation changes the action of the protein
Peptide hormone “first messenger”, attaches to molecule on the cell membrane initiating a reaction that produces a “second messenger” on the inside of the cell or allows for release of second messenger from a storage site out into the cytoplasm.
Basic Steps to Gonadotropin (LH/FSH) Induced Signaling:
1. Hormone Binds to the receptor (G-protein complex family) → activation of the G-protein
2. G-Protein activates Adenylate Cyclase (AC)
3. Activated AC generates Cyclic AMP (cAMP)
4. cAMP activates kinase protein kinase A (PKA) -which adds a phosphate group to the substrate ( phosphorylation).